Modeling with Linear Functions

Grade 8•45 minutes•8.f.b.4 Construct a function to model a linear relationship between two quantities. Determine the rate of change and initial value of the function from a description of a relationship or from two (x,y) values, including reading these from a table or from a graph. Interpret the rate of change and initial value of a linear function in terms of the situation it models, and in terms of its graph or a table of values.

Learning Objective

I can model real-world scenarios using linear functions by determining the rate of change and initial value from different representations.

Practice Questions

This lesson includes 7 practice questions to reinforce learning.

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1. A popular TikToker starts a dance challenge. On day 1, 50 people participate. Each day, 15 more people join the challenge. What is the initial value (starting number of participants) and the rate of change (number of new participants each day)?

2. A singer releases a new song. The number of streams increases linearly for the first week. After 2 days, the song has 10,000 streams. After 5 days, it has 25,000 streams. What is the rate of change in streams per day?

3. Write an equation to represent the following situation: A musician already has 20,000 followers and gains 500 new followers each day. Let y be the total number of followers and x be the number of days.

...and 4 more questions

Educational Video

Modeling with linear equations example 1 | Linear equations and functions | 8th grade | Khan Academy

Khan Academy

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